DNA from archived FFPE can be used for papillomavirus genotyping, but potential problems include paraffin as a physical barrier, DNA cross-linking, and PCR inhibitors. To address these complications, we combined a commercially available DNA isolation kit (Qiagen DNeasy) with a heat treatment and evaluated the resulting DNA with regards to HPV typing. DNA was extracted from 10-μm sections from 150 FFPE cancer samples. One protocol followed the manufacturer's recommendation, including paraffin removal by xylene and tissue lysis at 56°C. A second section was directly incubated at 120°C and subsequently lysed at 65°C. After spin-column purification, both extracts were tested with a linear array HPV genotyping assay. Additionally, cellular DNA yield, HPV16 DNA copies, and PCR inhibitors were assessed by real-time qPCR assays. Inadequate linear array HPV genotyping assay results were significantly more frequent (P = 0.0003) in xylene-treated (29/150, 19.3%) than in heat-treated extracts (8/150, 5.3%). HPV detection also differed, with 94/150 (62.7%) and 110/150 (73.3%) positive results, respectively (P = 0.0026). The heat method also yielded more PCR-amplifiable cellular DNA (8.2-fold; P < 0.001) and HPV16 copies (6.5-fold; P = 0.009), although PCR inhibitors also had a greater effect (P = 0.035). Aggressive heat treatment demonstrated an advantage over traditional xylene purification protocols, resulting in higher DNA yields and increased sensitivity for HPV testing.
Cited by (0)
The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention.
CME Disclosure: None of the authors disclosed any relevant financial relationships.